It’s no secret that a sonic boom rattled Central Florida early Sunday morning. What caused it was a nearly 2-year-old secret military space mission that ended at Kennedy Space Center.

The U.S. Air Force confirmed that its X-37B unmanned mini space shuttle landed at KSC after spending 718 days in orbit. The spacecraft lifted off from Cape Canaveral Air Force Station atop a United Launch Alliance Atlas V rocket on May 20, 2015.

What it has been doing circling the planet all this time is the secret part that military officials won’t discuss, though many experts believe it has intelligence-gathering equipment. What the military did confirm in a news release is that mini shuttle is “an experimental test program to demonstrate technologies for a reliable, reusable, unmanned space test platform for the U.S. Air Force.”

This was fourth space trip for the 29-foot-long, 11,000-pound mini shuttle, but it was the first time it has landed in Florida — which is why Sunday’s sonic boom provided an unexpected wake-up call.

Hundreds of people took to social media and contacted local media to find out what caused the big boom.

“Shook our house in Davenport and drove the dog into a brief frenzy,” Patrick Reikofski posted on his Twitter account.

But it wasn’t just Central Floridians who heard the spacecraft. Reports came from as far away as Tampa and Fort Myers.

“Didn't sound from where I live [like] a sonic boom,” said Cherie Doughan, who heard the noise near Cape Haze in Southwest Florida. “Sort of unnerving with things the way they are world wide.”

New video shows the sonic-boom-causing secret military space shuttle X-37B landing Sunday morning at Kennedy Space Center's Shuttle Landing Facility. It's unexpected arrival, with sonic boom, ended a nearly two-year mission in space for the mini-shuttle that was launched from Florida in May 2015.

Sonic booms used to be common and expected during the 30 years of NASA’s manned space shuttle program, with landings at Kennedy Space Center preceded by a loud double boom. But the last shuttle to land at KSC was Atlantis nearly six years ago when the program completed its final mission in July 2011.

SpaceX’s Falcon 9 rocket launches from the space coast also produce sonic booms, with the most recent one heard earlier this month.

But the X-37B’s booming return was unexpected. While there were rumors in February that the mini shuttle might return to Florida after its three previous flights ended at Vandenberg Air Force Base in California, officials would not confirm any itinerary for the spacecraft.

Sunday morning’s homecoming was announced by the Air Force at 7:57 a.m. in a tweet: “The Air Force #X37B #OTV4 has returned from orbit and landed safely at @NASAKennedy.” Video and photos of the craft’s landing were later released.

Another mission is scheduled to launch from Cape Canaveral later this year. How long it will last is unknown, but the Air Force said that with “an on-orbit time of 270 days or greater, the X-37B can stay in space for much longer.”

It’s also not known if the X-37B will return to Central Florida again — but if it does, you’ll certainly hear about it.

Air Force’s X-37B lands at KSC’s Shuttle Landing Facility

After several false dawns, the US Air Force’s X-37B mini-spaceplane has landed at the Kennedy Space Center (KSC) for the first time. With local reports of a sonic boom breaking through the morning air in areas of Florida, the Air Force confirmed the landing took place on Sunday at the historic Shuttle Landing Facility (SLF)

Kennedy Space Center shines as a multi-user spaceport:

The retirement of the Shuttle fleet left a rather large hole in the Kennedy Space Center’s (KSC’s) ability to launch and conduct human orbital space operations.

Specifically for the Air Force, the ability to use the SLF at Kennedy marks what is hoped to be the first of many uses of the SLF as the primary EOM landing facility for the X-37B – which the Air Force hopes to launch, land, and refurbish at KSC and the Cape Canaveral Air Force Station.

In fact, after landing, the X-37B is expected to be towed to OPF-1 for post-flight servicing operations. This operation has been tested several times with a mock-up space plane.

Opportunities to land the fourth X-37B mission came as early as February, with NOTAMs, orbital adjustments, and teams at KSC all primed.

These earlier attempts for the X-37B to approach the Kennedy Space Center, with the Range holding a space for several return opportunities, took the form of practice runs before weather became a major factor for what turned out to be a false landing attempt.

Based on the specific path the X-37B followed in its entry sequence this morning – understood to be a descending node entry over portions of the United States and Florida – large swathes of Central Florida were always going to be the first to be graced by the news of her return, via sonic booms as the X-37B rather insistently heralded its arrival back home. Twitter posts pre-empted this return, later confirmed by the Air Force.

The ability for this fourth mission to attempt a return to the runway at Kennedy followed three highly successful, completely autonomous deorbit, entry, and landing sequences of the first three X-37B flights, which all ended with precise touchdowns at the runway at Vandenberg Air Force Base, CA.

OTV-2 and OTV-3 landed without incident following a blown tire that led to minor underbelly damage of the OTV-1 vehicle (which subsequently flew the OTV-3 mission).

The expected mission duration for this fourth flight had been 637 days, but in the end, its 717 day mission duration beat OTV-3’s flight which lasted 674 days and 22 hours.

Previously, the first two OTV missions of the X-37B each extended the orbital mission duration of the previous flights, with OTV-2 being in space for 468 days and 14 hours over the OTV-1’s 224 days and 9 hours.

Moreover, the prolonged duration of the third and fourth X-37B missions highlight the secretive nature of the spaceplane, its missions, and its designed orbital lifetime – which is currently listed as 270 days… something which three of the four missions to date have shattered.

Presently, two X-37Bs are known to exist, with the first flying the OTV-1 and -3 missions and the second flying the OTV-2 and -4 missions.

In all, each X-37B is 8.92 m (29 feet 3 inches) in length, has a 4.55 m (14 foot 11 inch) wingspan, has a height of 2.9 m (9 feet 6 inches), and has a maximum lift off weight of 4,990 kg (11,000 lbs).

In preparation for landing at Kennedy, teams practiced landing drills and post-landing safing operations as well as emergency drills at the SLF, even using a mock up during tow tests.

With spacecraft observers noting a February change to the orbit, that – at the time – appeared to point to a landing attempt, along with activity at the SLF and NOTAM posts, the Pentagon deflected the interest in the potential landing, citing that the program was conducting a “regularly scheduled exercise” in a quote provided to Florida Today.

Interestingly, the actual landing on Sunday – three months later – had little by way of a heads up per the above observations.

Quelle: NS

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X-37B Orbital Test Vehicle-4 lands at Kennedy Space Center

By Secretary of the Air Force Public Affairs / Published May 07, 2017

The Air Force's X-37B Orbital Test Vehicle mission 4 lands at NASA 's Kennedy Space Center Shuttle Landing Facility, Fla., May 7, 2017. Managed by the Air Force Rapid Capabilities Office, the X-37B program is the newest and most advanced re-entry spacecraft that performs risk reduction, experimentation and concept of operations development for reusable space vehicle technologies. (U.S. Air Force courtesy photo)

The Air Force's X-37B Orbital Test Vehicle mission 4 lands at NASA 's Kennedy Space Center Shuttle Landing Facility, Fla., May 7, 2017. Managed by the Air Force Rapid Capabilities Office, the X-37B program is the newest and most advanced re-entry spacecraft that performs risk reduction, experimentation and concept of operations development for reusable space vehicle technologies. (U.S. Air Force courtesy photo)

“Today marks an incredibly exciting day for the 45th Space Wing as we continue to break barriers,” said Brig. Gen. Wayne Monteith, the 45th SW commander. “Our team has been preparing for this event for several years, and I am extremely proud to see our hard work and dedication culminate in today’s safe and successful landing of the X-37B.”

The OTV-4 conducted on-orbit experiments for 718 days during its mission, extending the total number of days spent on-orbit for the OTV program to 2,085 days.

"The landing of OTV-4 marks another success for the X-37B program and the nation," said Lt. Col. Ron Fehlen, X-37B program manager. "This mission once again set an on-orbit endurance record and marks the vehicle's first landing in the state of Florida. We are incredibly pleased with the performance of the space vehicle and are excited about the data gathered to support the scientific and space communities. We are extremely proud of the dedication and hard work by the entire team."

The X-37B is the newest and most advanced re-entry spacecraft. Managed by the Air Force Rapid Capabilities Office, the X-37B program performs risk reduction, experimentation and concept of operations development for reusable space vehicle technologies.

"The hard work of the X-37B OTV team and the 45th Space Wing successfully demonstrated the flexibility and resolve necessary to continue the nation's advancement in space," said Randy Walden, the director of the Air Force Rapid Capabilities Office. "The ability to land, refurbish, and launch from the same location further enhances the OTV's ability to rapidly integrate and qualify new space technologies."

The Air Force is preparing to launch the fifth X-37B mission from Cape Canaveral Air Force Station, Florida, later in 2017.

Quelle: USAF

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Sonic boom rattled Central Florida

ORLANDO, Fla. (WOFL FOX 35) - A top-secret military spacecraft is back on Earth, and it arrived in style, letting most of Central Florida know it was back in town.

Friends Christy Chesnut and Katie Dagenais heard it more than 40 miles away.

“I heard a huge bang,” Chesnut said. “I thought my son, who's 13, had fallen out of his bed and hit the floor.”

“The whole house shook,” Dagenais said. “The dog started barking and we just wondered what is this?”

This turned out to be the X-37B, an Air Force spacecraft that gave off a thunderous sonic boom when it landed at Cape Canaveral early this morning.

Dale Ketcham is Space Florida’s chief of strategic alliances.

He heard the boom while out walking his dog.

He says the unmanned military jet had just finished a classified 718-day mission in orbit.

The military says the jet was carrying out several experiments in orbit, like the effects of space on different materials.

They also revealed that the jet tested a new kind of thruster.

Ketcham says the spaceplane's success could mean booming business for the space coast.

“The Cape Canaveral Spaceport is the busiest, most successful spaceports in the world," he said. "It's one of the reasons Space Florida took over the shuttle landing facility because we're best equipped to grow that marketplace."

Good news for the local economy and for Dagenais, whose kids can watch the rockets launch from their backyard.

“It's funny, they don't think too hard about it when we say there's going to be a rocket launch," she said. "We'll sometimes have to encourage them to get up and come watch it, but once they're watching it they're really excited about it."

The space plane sent a sonic boom that rattled east-central Florida before 8 a.m., waking residents from their weekend slumber.

"Thought somebody crashed into my garage ... It was just a sonic boom ... Thanks @NASA for the scare!" said one woman on Twitter.

The X-37B, which looks like a small plane, made history by landing for the first time in Florida instead of California. It also set the on-orbit endurance record at 718 days, or almost two years.

"Our team has been preparing for this event for several years, and I am extremely proud to see our hard work and dedication culminate in today's safe and successful landing of the X-37B," said Brig. Gen. Wayne Monteith in a press release.

So what was this unmanned aircraft doing in space that long? There's been mystery surrounding this question for many years.

The Air Force maintains that the reusable plane "performs risk reduction, experimentation and concept of operations development for reusable space vehicle technologies."

Related video: Mysterious space plane returns to orbit01:47

But many speculate about other possible uses, including spying activities or testing of a secret space weapon.

This completed mission extends the program to 2,085 days in space.

The Air Force is preparing to launch the fifth X-37B mission from Florida's Cape Canaveral Air Force Station later in 2017.

Sonic booms awakened some Space Coast residents Sunday morning as an unmanned military space plane made its first touchdown at Kennedy Space Center, completing a nearly two-year, mostly classified mission.

The Air Force shortly after 8 a.m. reported that the experimental X-37B Orbital Test Vehicle had landed safely on NASA's former space shuttle runway.

Video posted by the Air Force from a runway camera showed the winged craft whiz overhead, touch down on wheels on the runway's north end and race down the three-mile, concrete strip before rolling to a stop in daylight. Official landing time: 7:47 a.m.

Crews wearing protective suits for hazardous operations met the mini-shuttle that measures about 29 feet long — about a quarter the length of NASA's shuttle orbiters — with a nearly 15-foot wingspan.

The fourth X-37B mission, known as OTV-4, launched from Cape Canaveral Air Force Station atop a United Launch Alliance Atlas V rocket on May 20, 2015, for a total mission duration of 718 days — the most yet by about six weeks.

"The landing of OTV-4 marks another success for the X-37B program and the nation," said Lt. Col. Ron Fehlen, X-37B program manager, in a press release. "This mission once again set an on-orbit endurance record and marks the vehicle's first landing in the state of Florida. We are incredibly pleased with the performance of the space vehicle and are excited about the data gathered to support the scientific and space communities. We are extremely proud of the dedication and hard work by the entire team."

An unmanned Air Force X-37B space plane on Sunday morning landed at Kennedy Space Center's Shuttle Landing Facility, completing a more than 700-day mission. (Photo: U.S. Air Force)

The landing was the first on KSC’s Shuttle Landing Facility by a spacecraft returning from orbit since Atlantis touched down nearly six years ago to conclude the final flight of NASA’s 30-year space shuttle program.

The much larger shuttle orbiters announced astronauts’ return home with twin sonic booms.

CLOSE

U.S. military officials say an unmanned spacecraft that orbited Earth since May 2015 has landed in Florida. The 29-foot long X37B is part of a test program to develop reusable spacecraft. (May 8) AP

Before Sunday, it was not known how widely noticed the return of the autonomously flown X-37B would be, but residents in northern Brevard County and across Central Florida reported hearing booms on social media.

The Air Force’s two reusable mini-shuttles have now each completed two missions in low Earth orbit, for a total of 2,085 days. The first mission launched in 2010 and flew for about 224 days.

Three previous landings occurred at Vandenberg Air Force Base in California.

But the program managed by the Air Force Rapid Capabilities Office and operated by Boeing has since consolidated operations at two of KSC's former shuttle hangars, enabling the mini-shuttles to launch and land in the same place.

High bay doors on one hangar identify the site as the “Home of the X-37B.”

"Our team has been preparing for this event for several years, and I am extremely proud to see our hard work and dedication culminate in today's safe and successful landing of the X-37B," said Brig. Gen. Wayne Monteith, commander of the Air Force's 45th Space Wing.

Details about the purpose of the space planes, which house smaller versions of shuttle payload bays, are mostly kept secret.

CLOSE

The U.S. Air Force is thinking about consolidating mysterious mini-shuttle operations at Kennedy Space Center or Cape Canaveral Air Force Station, the service said today. Video, narration by Caroline Perez. Reporting by Todd Halvorson. (9-27-12)

The Air Force says the vehicles are advancing reusable spacecraft technologies, allowing systems to be tested in space and then inspected back on the ground before being deployed on operational missions.

For example, the just-landed mission was known to have included tests of an upgraded electric thruster used by high-value national security satellites, and a NASA materials science experiment.

The Secure World Foundation has shot down speculation that the X-37B could be used to attack targets on the ground, saying that scenario has “near zero feasibility."

Instead, the foundation says, the platform “is likely to be used for flight testing new reusable space launch vehicle technologies (such as guidance and thermal protection) and on-orbit testing of new sensor technologies and satellite hardware primarily for space-based remote sensing.”

The Air Force says the fifth X-37B mission, OTV-5, is scheduled to launch later this year from Cape Canaveral.